Downhole packers are commonly used in many oilfield applications for the purpose of sealing against the flow of fluid to isolate one or more portions of a well bore for the purposes of testing, treating or producing the well. The packers are suspended in the well bore, or in a casing in the well bore, from a work string, or the like, and are activated, or set, so that one or more packer elements engage the inner surface of the well bore or casing to isolate various zones in the well bore.
Sand control methods are often used to prevent production of formation sand during downhole operations. According to one of these methods, a single trip process may be employed wherein perforation of a hydrocarbon interval (production zone) and setting of packing elements may be accomplished in one trip down the well bore. In a single trip perforation and packing process, a production screen is placed in the well bore, usually between an upper and lower packer. The packers are set and the annulus surrounding the production screen is then packed with a prepared sand/gravel slurry of a specific size designed to prevent the passage of formation sand. This also stabilizes the formation while causing minimal impairment to well productivity.
Conventional single trip sand control methods require a plugging device to be inserted into the above system to set the upper packer. To prevent the various tools and seals associated with the above-described assembly from becoming hydraulically locked after setting of the upper packer, a mechanical or hydraulic-operated venting device is typically inserted into the assembly to prevent hydraulic locking. However, this operation adds to the cost and time of the single trip sand control method.
Therefore, what is needed is an improved method for performing single trip perforating and packing operations within a well bore while eliminating the need to insert a plugging device to set the upper packer, thereby avoiding the problem of